Confused where the numbers "magical" in the diaphragm bracelets come from?Here's his explanation. One of the basic photography theory states that every time down the aperture diaphragm one-stop, means reducing the volume of light (entering through the lens) as much as half. In contrast, if we widen the aperture diaphragm one-stop, thus increasing the volume of light as much as double the previous. The explanation is as follows. Diaphragm Figures obtained from the comparison between the lens focal length and diameter of the lens surface that serves to collect light. (F / stop = F / Ø). So, if the lens has a diameter of 50 mm (diameter = diameter of the lens (glass) rather than the diameter of the filter holder) 50 mm wide as it is said he has a diaphragm f / 1 (50 mm: 50 mm). This is a very powerful lens collects light and is currently only produced by one camera manufacturer (Canon). From this it can be calculated - using a normal lens with maximum aperture f / 1.4 - how much the diameter of the lens used to collect light 50 mm: f / 1.4 = 35.7 mm (rounding of .......)²² 35.7142857
When we realize that light is responsible for collecting all the surface area of the lens is concerned, these calculations become more attractive again. Still remember junior high school lesson that formula to find the area of a circle equal to πr ² (pi r squared)? Or 22 / 7 times the radius times the radius? So, if the radius of the lens diameter 50 mm f / 1.4 is 17.85 mm (35.7: 2) then the lens surface area is π x 17, ² = 85 x 318.6225 = 1000.982105268413896122063591389 3.1415926535897932384626433832795 mm ² (rounded to 1001 mm ²)
When we reduce the aperture one stop to f / 2, the ability to gather light from the lens in question to be down by half. With the diaphragm f / 2, a virtual lens diameter had "converted" to 25 mm (50 mm: f / 2). The radius of these lenses to 12.5 mm. The surface area (virtual) lens in question becomes ² = π x 12.5 x 156.25 = 490.87385212340519350978802863742 3.1415926535897932384626433832795 mm ² (rounded to 491 mm ²)
Why not be half? Is not 491 mm ² yet half from 1001 mm ²?. Keep in mind that in photography there are a lot of rounding and compromise. Figures 491 mm ² is very close to half of the 1000 mm ². Besides wide difference of 9 mm ² will be very little difference in results shooting. However, if you're still curious, too, we see just why it is not really made half (500 mm ²). If so, we count back to 500 mm ²: π = 500: 3,1415926535897932384626433832795 = 159.15494309189533576888376337251 Roots of 159.15494309189533576888376337251 is the radius of the lens, namely 12.615662610100800241235747611828 mmFrom here the figures obtained as 25.231325220201600482471495223657 mm diameter. f / stop lens concerned adalah50 mm: 25.231325220201600482471495223657 = f / 1.9816636488030055066725143825606
The question now is, can a series of number is to be written on the bracelet the small width of the diaphragm? Moreover is not it very obvious now that the actual f / 1.98 onwards it was very close to f / 2?We continue by following the diaphragm aperture, namely f / 2.8 all to show more about rounding and compromise earlier.Virtual diameter of 50 mm lens at f / 2.8 is 50mm: f / 2.8 = 17.85 mm (from 17.857142857142857142857142857143) The fingers are 17.85: 2 = 8.925 mmSurface area: π x 8.925 ² = 3.1415926535897932384626433832795 x 79.655625 = 250.2455263171034740305158978472 mm ² or 250 mm ². Uhapir half of the previous surface area and a quarter of the surface area of the diaphragm f / 1.4.With the formula above, the surface area at f / 4 adalah122, 71846303085129837744700715936 mm ² (rounded to 123 mm ² once again almost half of previous)The surface area of the lens from one diaphragm to another diaphragm ranged approximately half (if understated) or twice (when raised) from the previous value. In conjunction with the shutter speed, seems clear enough that by reducing the volume of the light half (-1 stop) automatically takes twice as long (+1 stop), and vice versa, by doubling the volume of light, the time needed also becomes faster two fold.
Then, do you know that there are several versions about the true meaning of f / stop? F / stop (small f) can mean one below, the abbreviation of fenestra (Latin) meaning "window" (interpreted as opening diaphragm forming a "window "for light to enter through the lens). Abbreviations of function (function) or fraction (fraction) symbol of the focal length (focal length) divided by the diameter of the opening (aperture) of a legendary photographers (Ansel Adams) who feel the form letter 'f' for opening the diaphragm more "beautiful" and "art "American standard of writing that was popular in the early 20th century ago (eg, U.S. 1 to f / 4, US4 to f / 8, and so on).Whichever you believe, he explained the word "stop" represents a shift of the aperture diaphragm to the other diaphragm which has a stopping point on the bracelet regulator.
When we realize that light is responsible for collecting all the surface area of the lens is concerned, these calculations become more attractive again. Still remember junior high school lesson that formula to find the area of a circle equal to πr ² (pi r squared)? Or 22 / 7 times the radius times the radius? So, if the radius of the lens diameter 50 mm f / 1.4 is 17.85 mm (35.7: 2) then the lens surface area is π x 17, ² = 85 x 318.6225 = 1000.982105268413896122063591389 3.1415926535897932384626433832795 mm ² (rounded to 1001 mm ²)
When we reduce the aperture one stop to f / 2, the ability to gather light from the lens in question to be down by half. With the diaphragm f / 2, a virtual lens diameter had "converted" to 25 mm (50 mm: f / 2). The radius of these lenses to 12.5 mm. The surface area (virtual) lens in question becomes ² = π x 12.5 x 156.25 = 490.87385212340519350978802863742 3.1415926535897932384626433832795 mm ² (rounded to 491 mm ²)
Why not be half? Is not 491 mm ² yet half from 1001 mm ²?. Keep in mind that in photography there are a lot of rounding and compromise. Figures 491 mm ² is very close to half of the 1000 mm ². Besides wide difference of 9 mm ² will be very little difference in results shooting. However, if you're still curious, too, we see just why it is not really made half (500 mm ²). If so, we count back to 500 mm ²: π = 500: 3,1415926535897932384626433832795 = 159.15494309189533576888376337251 Roots of 159.15494309189533576888376337251 is the radius of the lens, namely 12.615662610100800241235747611828 mmFrom here the figures obtained as 25.231325220201600482471495223657 mm diameter. f / stop lens concerned adalah50 mm: 25.231325220201600482471495223657 = f / 1.9816636488030055066725143825606
The question now is, can a series of number is to be written on the bracelet the small width of the diaphragm? Moreover is not it very obvious now that the actual f / 1.98 onwards it was very close to f / 2?We continue by following the diaphragm aperture, namely f / 2.8 all to show more about rounding and compromise earlier.Virtual diameter of 50 mm lens at f / 2.8 is 50mm: f / 2.8 = 17.85 mm (from 17.857142857142857142857142857143) The fingers are 17.85: 2 = 8.925 mmSurface area: π x 8.925 ² = 3.1415926535897932384626433832795 x 79.655625 = 250.2455263171034740305158978472 mm ² or 250 mm ². Uhapir half of the previous surface area and a quarter of the surface area of the diaphragm f / 1.4.With the formula above, the surface area at f / 4 adalah122, 71846303085129837744700715936 mm ² (rounded to 123 mm ² once again almost half of previous)The surface area of the lens from one diaphragm to another diaphragm ranged approximately half (if understated) or twice (when raised) from the previous value. In conjunction with the shutter speed, seems clear enough that by reducing the volume of the light half (-1 stop) automatically takes twice as long (+1 stop), and vice versa, by doubling the volume of light, the time needed also becomes faster two fold.
Then, do you know that there are several versions about the true meaning of f / stop? F / stop (small f) can mean one below, the abbreviation of fenestra (Latin) meaning "window" (interpreted as opening diaphragm forming a "window "for light to enter through the lens). Abbreviations of function (function) or fraction (fraction) symbol of the focal length (focal length) divided by the diameter of the opening (aperture) of a legendary photographers (Ansel Adams) who feel the form letter 'f' for opening the diaphragm more "beautiful" and "art "American standard of writing that was popular in the early 20th century ago (eg, U.S. 1 to f / 4, US4 to f / 8, and so on).Whichever you believe, he explained the word "stop" represents a shift of the aperture diaphragm to the other diaphragm which has a stopping point on the bracelet regulator.
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